Object recognition apparatus and vehicle travel controller using same

ABSTRACT

The present invention provides an object recognition apparatus which, in a vehicle that detects an object present behind (including obliquely behind) the vehicle using a radio wave radar, is able to precisely recognize the position of the object present behind (including obliquely behind) the vehicle during traveling on a curve and a lane change, and a vehicle travel controller using the same. An object recognition apparatus is provided with: an image capturing unit which captures an image of an environment in front of a vehicle; a lane detection unit which detects a lane in front of the vehicle on the basis of the image captured by the image capturing unit; a lane position estimation unit which estimates the position of a lane behind the vehicle on the basis of the lane detected by the lane detection unit and the travel history of the vehicle; a rear object detection unit which detects an object present behind the vehicle; and a relative position calculation unit which calculates the relative position of the object detected by the rear object detection unit with respect to the position of the lane estimated by the lane position estimation unit.

TECHNICAL FIELD

The present invention relates to an object recognition apparatus and avehicle travel controller using the same. Particularly, the inventionrelates to a vehicle travel controller that controls a travel state ofan own vehicle by recognizing a position of an object existing at a rearside including an oblique rear side of the own vehicle.

BACKGROUND ART

Recently, there is known a technique disclosed in, for example, PTL 1 asa technique of detecting a position of an object existing behind an ownvehicle.

An object position detection device disclosed in PTL 1 includes astorage unit which stores a travel position of an own vehicle travelingon a road, a detection unit which detects a position of a rear objectexisting behind the own vehicle, and an estimation unit which estimatesa vehicle lane on which the rear object is located on the basis of arelative positional relation between the past travel position of the ownvehicle stored in the storage unit and the position of the rear objectdetected by the detection unit, wherein the estimation unit estimatesthe vehicle lane on which the rear object is located on the basis of adistance between the position of the rear object and a travel trackobtained from the past travel position of the own vehicle.

CITATION LIST Patent Literature

PTL 1: JP 2010-127908 A

SUMMARY OF INVENTION Technical Problem

Incidentally, there is a case where a driver of a vehicle traveling on acertain vehicle lane changes vehicle lanes, for example, when overtakinga preceding vehicle or turning left or right. Likewise, when the ownvehicle changes the vehicle lanes, the travel position of the ownvehicle moves across the vehicle lane.

In the object position detection device disclosed in PTL 1, the vehiclelane on which the rear object is located is estimated on the basis ofthe distance between the position of the rear object and the traveltrack obtained from the past travel position of the own vehicle. Forthis reason, as described above, when the own vehicle changes thevehicle lane and the past travel position of the own vehicle movesacross the vehicle lane, the own vehicle cannot accurately recognize thevehicle lane on which the own vehicle travels or the vehicle lane onwhich the rear object is located as illustrated in FIG. 20. For example,there is a possibility that an erroneous warning sound may be generatedfor the driver who drives the own vehicle. Further, in the objectposition detection device disclosed in PTL 1, there is a case where thevehicle lane on which the own vehicle travels or the vehicle lane onwhich the rear object is located cannot be accurately recognized evenwhen the own vehicle travels on a curved vehicle lane. Thus, asdescribed above, for example, there is a possibility that an erroneouswarning sound may be generated for the driver who drives the ownvehicle.

Further, in the object position detection device disclosed in PTL 1, amillimeter wave radar is used as the detection unit that detects theposition of the rear object existing behind the own vehicle. However,for example, when the own vehicle travels on a road provided with aguardrail, a signal output from a radio wave radar such as a millimeterwave radar is reflected by the guardrail. As a result, a problem arisesin that the position of the rear object and the vehicle lane on whichthe rear object is located cannot be accurately estimated.

The invention is made in view of the above-described problems and anobject of the invention is to provide an object recognition apparatuscapable of accurately recognizing a position of an object existing at arear side including an oblique rear side of an own vehicle and a vehicletravel controller using the same.

Solution to Problem

In order to solve the problems, an object recognition apparatusaccording to the present invention is an object recognition apparatusthat recognizes a position of an object existing behind an own vehicle,including: an image sensing device that captures an image of anenvironment at the front or rear side of an own vehicle; a vehicle lanedetection unit that detects a vehicle lane at the front or rear side ofthe own vehicle on the basis of the image captured by the image sensingdevice; a vehicle lane position estimation unit that estimates aposition of a vehicle lane behind the own vehicle on the basis of thevehicle lane detected by the vehicle lane detection unit and a travelhistory of the own vehicle; a rear object detection unit that detects anobject existing behind the own vehicle; and a relative positioncalculation unit that calculates a relative position of the objectdetected by the rear object detection unit with respect to the positionof the vehicle lane estimated by the vehicle lane position estimationunit.

In addition, an object recognition apparatus according to the presentinvention is an object recognition apparatus that recognizes a positionof an object existing behind an own vehicle, including: an image sensingdevice that captures an image of an environment at the front or rearside of an own vehicle; a solid object detection unit that detects astationary object at the front or rear side of the own vehicle on thebasis of the image captured by the image sensing device; a solid objectposition estimation unit that estimates a position of a stationaryobject behind the own vehicle on the basis of the stationary objectdetected by the solid object detection unit and a travel history of theown vehicle; a rear object detection unit that detects an objectexisting behind the own vehicle; and a relative position calculationunit that calculates a relative position of the object detected by therear object detection unit with respect to the position of thestationary object estimated by the solid object position estimationunit.

In addition, a vehicle travel controller according to the presentinvention is a vehicle travel controller that controls a travel state ofan own vehicle on the basis of a position of an object recognized by theobject recognition apparatus.

Advantageous Effects of Invention

According to the invention, the vehicle lane or the stationary object infront of the own vehicle is detected on the basis of an image capturedby the image sensing device capturing an image of an environment infront of the own vehicle, the position of the vehicle lane or thestationary object behind the own vehicle is estimated on the basis ofthe detected vehicle lane or stationary object and the travel history ofthe own vehicle, and the relative position of the object existing behindthe own vehicle with respect to the estimated position of the vehiclelane or the stationary object is calculated. Accordingly, it is possibleto accurately recognize the position of the object existing at the rearside including the oblique rear side of the own vehicle.

The above-described objects, configurations, and advantages are provedby the description of the embodiments below.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a configuration diagram illustrating a configuration of afirst embodiment of a vehicle travel controller using an objectrecognition apparatus according to the invention.

FIG. 2 is a diagram illustrating an example of an image captured by acamera illustrated in FIG. 1.

FIG. 3 is a diagram illustrating an example of a position of a rearvehicle and a vehicle lane with respect to an own vehicle.

FIG. 4 is a diagram illustrating a change in time of a coordinate systemusing an own vehicle as an original point.

FIG. 5 is a diagram illustrating an example of vehicle lane positioninformation stored in a vehicle lane position information storage unitillustrated in FIG. 1.

FIG. 6 is a diagram illustrating an example of a positional relationbetween a rear vehicle and a vehicle lane with respect to an ownvehicle.

FIG. 7 is a diagram illustrating another example of a positionalrelation between a rear vehicle and a vehicle lane with respect to anown vehicle.

FIG. 8 is a flowchart illustrating a process flow of the vehicle travelcontroller illustrated in FIG. 1.

FIG. 9 is a configuration diagram illustrating a configuration of asecond embodiment of the vehicle travel controller using the objectrecognition apparatus according to the invention.

FIG. 10 is a diagram illustrating an example of an image captured by astereo camera illustrated in FIG. 9.

FIG. 11 is a diagram illustrating an example of a positional relationbetween a rear vehicle and a stationary object with respect to an ownvehicle.

FIG. 12 is a diagram illustrating an example of solid object positioninformation stored in a solid object position information storage unitillustrated in FIG. 9.

FIG. 13 is a diagram illustrating an example of a positional relationbetween a rear vehicle and a stationary object with respect to an ownvehicle.

FIG. 14 is a diagram illustrating another example of a positionalrelation between a rear vehicle and a stationary object with respect toan own vehicle.

FIG. 15 is a flowchart illustrating a process flow of the vehicle travelcontroller illustrated in FIG. 9.

FIG. 16 is a configuration diagram illustrating a configuration of athird embodiment of the vehicle travel controller using the objectrecognition apparatus according to the invention.

FIG. 17 is a diagram illustrating an example of an image captured by acamera illustrated in FIG. 16.

FIG. 18 is a diagram illustrating an example of a positional relationbetween a rear vehicle and a vehicle lane with respect to an ownvehicle.

FIG. 19 is a diagram illustrating an example of vehicle lane positioninformation stored in a vehicle lane position information storage unitillustrated in FIG. 16.

FIG. 20 is a diagram illustrating a position of a rear object detectedby a background art.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the invention will be described withreference to the drawings.

<First Embodiment>

FIG. 1 is a configuration diagram illustrating a configuration of afirst embodiment of a vehicle travel controller using an objectrecognition apparatus according to the invention.

As illustrated in the drawing, a vehicle travel controller 50 mainlyincludes an object recognition apparatus 20 which recognizes a positionof an object existing behind an own vehicle, a steering angle sensor 21,a yaw rate sensor 22, a vehicle wheel speed sensor 23, a navigationsystem 24, and a control unit 25 which generates various control signalsfor controlling a travel state and the like of an own vehicle on thebasis of a position of an object recognized by the object recognitionapparatus 20.

Further, the object recognition apparatus 20 includes a rear objectdetection device 1, a vehicle lane detection device 2, and a travelhistory calculation device 3.

The rear object detection device 1 is used to detect an object (forexample, a moving or stopped/parked vehicle (an automobile, amotorcycle, a bicycle, or the like) or a people) existing at an obliquerear side (hereinafter, referred to as a rear side) of the own vehicleand includes, for example, a plurality of radio wave radars (rear objectdetection units) 7 provided behind the left and right sides of the ownvehicle. The radio wave radars 7 are able to detect a relative position(a distance and a direction) and a relative speed of an object behindthe own vehicle with respect to the own vehicle by transmitting radiowaves to a predetermined range behind the own vehicle and receivingreflected waves from the object existing in the range.

Specifically, for example, as illustrated in FIG. 3, radio wave radars 7a and 7 b are mounted behind left and right sides of an own vehicle VS.Here, the radio wave radar 7 a which is provided behind the left side ofthe own vehicle VS sets an area Aa behind the left side of the ownvehicle VS as a detection area and the radio wave radar 7 b which isprovided behind the right side of the own vehicle VS sets an area Abbehind the right side of the own vehicle VS as a detection area. Forexample, when a target vehicle VT exist on a vehicle lane adjacent tothe right side of the own vehicle VS, the radio wave radar 7 detects arelative speed and a position (P, Q) of the target vehicle VT withrespect to the own vehicle VS in a coordinate system X-Y using a centerof the own vehicle VS as an original point by the use of the radio waveradars 7 a and 7 b.

The vehicle lane detection device 2 is used to detect a vehicle lane (avehicle travel lane) in front of the own vehicle and includes, forexample, a camera (a front camera) (an image sensing device) 8 which isdisposed at an upper portion of a center of a wind shield of the ownvehicle and captures an environment in front of the own vehicle and avehicle lane detection unit 9 which detects a vehicle lane in front ofthe own vehicle on the basis of an image captured by the camera 8.

The camera 8 is configured as, for example, a CMOS camera and isattached to the own vehicle to have an optical axis directed obliquelydownward at the front side of the own vehicle. Then, as illustrated inFIG. 2, the camera 8 captures an image of a peripheral environmentincluding a road in the range of several tens of meters in front of theown vehicle and transmits the captured image to the vehicle lanedetection unit 9.

The vehicle lane detection unit 9 performs, for example, a binarizationprocess or a feature point extraction process based on the imagecaptured by the camera 8 to select a pixel (a road dividing linecandidate point) which is considered as a road dividing line (includinga white line, a yellow line, a broken line, or bott's-dots) on a roadfrom the image, recognizes continuously arranged road dividing linecandidate points as a road dividing line constituting the vehicle laneto obtain the position, and transmits information on the position to thevehicle lane position estimation unit 4 of the travel historycalculation device 3. In the image captured by the camera 8 illustratedin FIG. 2, the right road dividing lines are indicated by R1 to R3 andthe left road dividing lines are indicated by L1 to L3 in a directionfrom the front side. In FIG. 3, the positions of the road dividing linesillustrated in FIG. 2 in the coordinate system X-Y using the center ofthe own vehicle as an original point are respectively indicated by R1:(xr_1, yr_1), R2: (xr_2, yr_2), R3: (xr_3, yr_3), L1: (xl_1, yl_1), L2:(xl_2, yl_2), and L3: (xl_3, yl_3). Additionally, in FIGS. 2 and 3, anexample is illustrated in which the positions of the road dividing linesare respectively indicated as three points at the left and right sides,but the same applies to a case where two points or less or four pointsor more are obtained or a case where the positions are approximated to aline or a curve.

Further, various methods have been developed to recognize the roaddividing line or the vehicle lane defined by the road dividing line. Forexample, a method of extracting a road shoulder or a median strip by apattern matching can be also used. Further, the vehicle lane detectiondevice 2 can be, of course, commonly used together with various vehiclelane detection devices used in, for example, a vehicle lane keep assistdevice (also referred to as a lane keep assist) or a vehicle lanedeparture warning device (also referred to as a lane departure warning).

The travel history calculation device 3 is used to calculate a positionof an object existing behind the own vehicle on the basis of theinformation transmitted from the rear object detection device 1 or thevehicle lane detection device 2 and to output information necessary forthe travel control of the own vehicle to the control unit 25 and mainlyincludes a travel history calculation unit 11, the vehicle lane positionestimation unit 4, a vehicle lane position information storage unit 10,a relative position calculation unit 5, and a determination unit 6.

The travel history calculation unit 11 calculates a travel history ofthe own vehicle on the basis of information obtained by the steeringangle sensor 21, the yaw rate sensor 22, the vehicle wheel speed sensor23 serving as a vehicle speed sensor, and the navigation system 24constituting the vehicle travel controller 50 and transmits thecalculation result to the vehicle lane position estimation unit 4.

Specifically, as illustrated in FIG. 4, on the assumption that thecoordinate system using the center of the own vehicle as an originalpoint at the time t(n) is indicated by X(n)-Y(n), the coordinate systemusing the center of the own vehicle as an original point at the timet(n+1) is indicated by X(n+1)-Y(n+1), the speed of the own vehicle VS atthe time t(n) is indicated by V_(n), and the traveling direction isindicated by θ_(n), a positional change amount (Δx, Δy) of the ownvehicle VS for Δt=(t(n+1)−t(n)) is expressed by Equation (1) below.

$\begin{matrix}{\left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\mspace{619mu}} & \; \\{\begin{bmatrix}{\Delta\; x} \\{\Delta\; y}\end{bmatrix} = {\begin{bmatrix}{\cos\left( \theta_{n} \right)} \\{\sin\left( \theta_{n} \right)}\end{bmatrix}*V_{n}^{*}\Delta\; t}} & (1)\end{matrix}$

Next, a direction of the own vehicle VS at the time t(n+1)=t(n)+Δt willbe considered. When the rotation angular velocity of the own vehicle VSat the time t(n) to be estimated by the steering angle sensor 21 or theyaw rate sensor 22 is indicated by ω_(n), the traveling directionθ_(n+1) of the own vehicle VS at the time t(n+1) is estimated byEquation (2).[Equation 2]θ_(n+1)=θ_(n)+ω_(n) ·Δt  (2)

Further, an angle Δθ_(n) formed by the coordinate system X(n)-Y(n) usingthe center of the own vehicle as an original point at the time t(n) andthe coordinate system X(n+1)-Y(n+1) using the center of the own vehicleas an original point at the time t(n+1) is expressed by Equation (3)below.[Equation 3]Δθ_(n)=ω_(n) ·Δt  (3)

Here, the speed V_(n) of the own vehicle VS in time is obtained by thevehicle wheel speed sensor 23, the navigation system 24, or the like andthe traveling direction θ_(n) or the rotation angular velocity ω_(n) ofthe own vehicle VS is obtained by the steering angle sensor 21, the yawrate sensor 22, the navigation system 24, or the like.

The vehicle lane position estimation unit 4 converts the vehicle laneposition information (corresponding to the road dividing line position)output from the vehicle lane detection device 2 into the coordinatesystem using the center of the own vehicle as an original point in timeon the basis of the above-described relational equation of the travelhistory calculation unit 11 and stores the conversion result in thevehicle lane position information storage unit 10. As for the conversionof the coordinate system at that time, a case will be considered inwhich a point P fixed to a ground surface is converted from thecoordinate system X(n)-Y(n) using the center of the own vehicle as anoriginal point at the time t(n) to the coordinate system X(n+1)-Y(n+1)at the time t(n+1). When the coordinate of the point P in the coordinatesystem at the time t(n) is indicated by (x(t(n)), y(t(n))) and thecoordinate of the point P at the time t(n+1) is indicated by (x(t(n+1)),y(t(n+1))), a relation of the coordinate is expressed by Equation (4)below.

$\begin{matrix}{\left\lbrack {{Equation}\mspace{14mu} 4} \right\rbrack\mspace{619mu}} & \; \\\begin{matrix}{\begin{bmatrix}{x\left( {t\left( {n + 1} \right)} \right)} \\{y\left( {t\left( {n + 1} \right)} \right)}\end{bmatrix} = {\begin{bmatrix}{\cos\left( {\Delta\theta}_{n} \right)} & {- {\sin\left( {\Delta\theta}_{n} \right)}} \\{\sin\left( {\Delta\theta}_{n} \right)} & {\cos\left( {\Delta\theta}_{n} \right)}\end{bmatrix} \times \left\lbrack {\begin{bmatrix}{x\left( {t(n)} \right)} \\{y\left( {t(n)} \right)}\end{bmatrix} - \begin{bmatrix}{\Delta\; x} \\{\Delta\; y}\end{bmatrix}} \right\rbrack}} \\{= {{R\left( {\Delta\theta}_{n} \right)} \times \begin{bmatrix}{{x\left( {t(n)} \right)} - {\Delta\; x}} \\{{y\left( {t(n)} \right)} - {\Delta\; y}}\end{bmatrix}}}\end{matrix} & (4)\end{matrix}$

In this way, the vehicle lane position estimation unit 4 converts thevehicle lane position detected in the past as the coordinate systemusing the center of the own vehicle as an original point in time on thebasis of the information detected from the travel history calculationunit 11 and stores the conversion result in the vehicle lane positioninformation storage unit 10. At the same time, the vehicle lane positionestimation unit 4 acquires the vehicle lane position information at acurrent time point from the vehicle lane detection device 2 andadditionally stores the vehicle lane position information in the vehiclelane position information storage unit 10.

Specifically, as illustrated in FIG. 5, the vehicle lane positionestimation unit 4 first stores the vehicle lane position informationoutput from the vehicle lane detection device 2 at the time t(n) in thevehicle lane position information storage unit 10. For example, asillustrated in FIGS. 2 and 3, the coordinate information (xr_1(t(n)),yr_1(t(n))), (xr_2(t(n)), yr_2(t(n))), (xr_3(t(n)), yr_3(t(n))) isstored while a position (that is, vehicle lane information) of a rightroad dividing line obtained from an image captured by the camera 8 isset as positions R1 to R3 in the coordinate system X-Y using the centerof the own vehicle as an original point at the time t(n). Similarly,although there is no description in FIG. 5, the coordinate information(xl_1(t(n)), yl_1(t(n))), (xl_2(t(n)), yl_2(t(n))), (xl_3(t(n)),yl_3(t(n))) is stored while a position (that is, vehicle laneinformation) of a left road dividing line obtained from an imagecaptured by the camera 8 is set as positions L1 to L3 in the coordinatesystem X-Y using the center of the own vehicle as an original point.

Next, when the time elapses from t(n) to t(n+1), the vehicle laneposition estimation unit 4 converts the positions R1 to R3 of the rightroad dividing line and the positions L1 to L3 of the left road dividingline into position information in the coordinate system X(n+1)-Y(n+1)using the center of the own vehicle as an original point at the timet(n+1) by Equation (4) and stores the conversion result in the vehiclelane position information storage unit 10.

In accordance with a series of conversion, coordinate information fromthe positions R1 to R3 of the right road dividing line detected at thetime t(n) to positions Rm1 to Rm3 of the right road dividing linedetected at the time t(n+m) is totally stored as the vehicle laneposition information in the vehicle lane position information storageunit 10 at the time t(n+m) (see FIG. 5). Similarly, even in the leftroad dividing line, the position information of the road dividing linedetected by the vehicle lane detection device 2 from the time t(n) tothe time t(n+m) is stored as the vehicle lane position information inthe vehicle lane position information storage unit 10.

In addition, the vehicle lane position information storage unit 10stores the vehicle lane position information altogether from the past.However, it is practical to sequentially delete the vehicle laneposition information stored for a predetermined time or more or thevehicle lane position information in which a distance from the ownvehicle becomes a predetermined value or more from the vehicle laneposition information storage unit 10 in order to prevent the overflow ofthe storage capacity.

In this way, when the vehicle lane position information is recognized intime and the past vehicle lane position information is used, the vehiclelane position behind the own vehicle can be accurately estimated.

The relative position calculation unit 5 is used to calculate a relativeposition of an object detected by the rear object detection device 1 atthe position of the vehicle lane behind the own vehicle stored in thevehicle lane position information storage unit 10.

Specifically, when the rear object detection device 1 detects the targetvehicle VT and the relative speed and the position (P, Q) of the targetvehicle VT with respect to the own vehicle VS in the coordinate systemX-Y using the center of the own vehicle as an original point asillustrated in FIG. 6 or 7, the relative position calculation unit 5calculates two points (two points of each of the left and right roaddividing lines) closest to each other in the traveling direction (theY-axis direction) of the own vehicle VS from the vehicle lane positioninformation stored in the vehicle lane position information storage unit10. In the vehicle lane position information illustrated in FIG. 6 or 7,positions Rn1 and Rn2 of the right road dividing line are closest toeach other in the Y-axis direction and positions Ln1 and Ln2 of the leftroad dividing line are closest to each other in the Y-axis direction.Then, the relative position calculation unit 5 obtains a line connectingtwo points Rn1 and Rn2 of the right road dividing line position, obtainsan X-direction distance xr_np at a place corresponding to the positionof the line in the Y-axis direction of the target vehicle VT, calculatesa large/small relation between a value of the distance xr_np and a valueP of the target vehicle VT in the X-axis direction, and transmits thecalculation result to the determination unit 6.

The determination unit 6 determines whether an object detected by therear object detection device 1 exists on a predetermined vehicle lane(for example, a vehicle lane which needs to generate a warning) on thebasis of the large/small relation transmitted from the relative positioncalculation unit 5.

Specifically, the determination unit 6 determines whether the targetvehicle VT exists at the inside or the outside of the right roaddividing line on the basis of the large/small relation transmitted fromthe relative position calculation unit 5, for example, as illustrated inFIG. 6 and transmits the determination result to the control unit 25.Further, FIG. 6 illustrates an example in which the value P in theX-axis direction of the target vehicle VT is larger than the distancexr_np to the right road dividing line, that is, the target vehicle VTexists on the right adjacent vehicle lane. By the above-describedcalculation, it is possible to determine whether the target vehicle VTexists at the right adjacent vehicle lane with respect to the vehiclelane on which the own vehicle VS travels.

Meanwhile, FIG. 7 illustrates an example in which the value P in theX-axis direction of the target vehicle VT is smaller than the distancexr_np to the right road dividing line. In this case, the above-describedcalculation is also continuously performed on the left road dividingline. Accordingly, it is possible to determine whether the targetvehicle VT exists at the rear side within the vehicle lane which issimilar to the vehicle lane on which the own vehicle VS travels.

The control unit 25 generates various control signals for controllingthe travel state and the like of the own vehicle on the basis of theinformation transmitted from (the determination unit 6 of the travelhistory calculation device 3 of) the object recognition apparatus 20.

Specifically, when the determination unit 6 determines that the objectdetected by the rear object detection device 1 exists on a predeterminedvehicle lane (for example, a vehicle lane which generates a warning),the control unit 25 generates, for example, a control signal forcontrolling (regulating) a steering operation, a control signal forcontrolling a vehicle speed of the own vehicle, or a control signal forgenerating a warning (a warning sound or a warning display on a controlpanel) for a driver and transmits such a control signal to anappropriate in-vehicle device.

A flow of a series of processes which is performed by theabove-described vehicle travel controller 50 will be described withreference to FIG. 8. First, in step S101, a vehicle lane position in theabove-described coordinate system X-Y using the own vehicle as anoriginal point is obtained by the vehicle lane detection device 2 of theobject recognition apparatus 20 according to the method described withreference to FIGS. 2 and 3.

Next, in step S102, the vehicle lane position obtained in step S101 isstored in the vehicle lane position information storage unit 10 as thecoordinate system using the own vehicle as an original point by thevehicle lane position estimation unit 4 of the travel historycalculation device 3.

Next, in step S103, the movement amount of the own vehicle is estimatedby the travel history calculation unit 11 for Δt seconds on the basis ofthe information obtained by the steering angle sensor 21, the yaw ratesensor 22, the vehicle wheel speed sensor 23, and the navigation system24 constituting the vehicle travel controller 50 and the coordinatesystem X(n)-Y(n) using the own vehicle as an original point at the timet(n) and the coordinate system X(n+1)-Y(n+1) using the own vehicle as anoriginal point at the time t(n+1) are obtained by Equation (1) toEquation (3).

Next, in step S104, the vehicle lane position information detected inthe past by the vehicle lane detection device 2 is converted to thecoordinate system using the own vehicle as an original point at acurrent time on the basis of Equation (4) to estimate the vehicle laneposition behind the own vehicle by the vehicle lane position estimationunit 4 and the conversion result is stored in the vehicle lane positioninformation storage unit 10.

Next, in step S105, a rear object (a target vehicle or the like)including a rear side is detected by the rear object detection device 1and a position coordinate (P, Q) of the target vehicle is obtained.

Next, in step S106, a relative position between the vehicle laneposition information stored in step S104 and the target vehicle detectedin step S105 is obtained by the relative position calculation unit 5.More specifically, when the rear object detection device 1 detects thetarget vehicle and the position (P, Q) of the target vehicle in thecoordinate system X-Y using the own vehicle as an original point asdescribed above, the vehicle lane position information for two pointsclosest to each other in the traveling direction (the Y-axis direction)of the own vehicle is selected from the vehicle lane positioninformation stored in the vehicle lane position information storage unit10. When the X-direction distance of the target vehicle with respect tothe vehicle lane positions of two points closest to each other in theY-axis direction is obtained, the relative position of the targetvehicle with respect to the vehicle lane can be estimated.

Next, in step S107, the determination unit 6 determines a certainvehicle lane (a vehicle lane on which the own vehicle travels, a rightadjacent vehicle lane, a left adjacent vehicle lane, or two or moreseparated vehicle lanes) on which the target vehicle behind the ownvehicle travels on the basis of the information of the relative positionof the target vehicle with respect to the vehicle lane obtained in stepS106. Specifically, it is determined whether the target vehicle existsin an area (a vehicle lane) corresponding to a warning object. When itis determined that the target vehicle exists in the area (the vehiclelane) corresponding to the warning object, it is determined whether toactually output a warning sound from the information including theposition and the speed (for example, information on whether the targetvehicle approaches the own vehicle) of the target vehicle in step S108.

Then, when it is determined that a warning sound needs to be actuallyoutput in step S108, a control signal is generated by the control unit25 to output a warning sound in step S109.

In addition, a series of these processes are repeated whenever ΔTseconds elapse.

In this way, according to the first embodiment, in the vehicle thatdetects an object existing at the rear side including the oblique rearside of the own vehicle by the radio wave radar 7 such as a millimeterwave radar, the vehicle lane in front of the own vehicle is detected onthe basis of the image captured by the camera 8 capturing an image of anenvironment in front of the own vehicle, the position of the vehiclelane behind the own vehicle is estimated on the basis of the detectedvehicle lane and the travel history of the own vehicle, and the relativeposition of the object existing behind the own vehicle with respect tothe estimated position of the vehicle lane is calculated. Accordingly,it is possible to accurately recognize the position of the objectexisting at the rear side including the oblique rear side of the ownvehicle, that is, the vehicle lane on which the object is located evenwhen the own vehicle travels on a curve or the vehicle lane is changed.

<Second Embodiment>

FIG. 9 is a configuration diagram illustrating a configuration of asecond embodiment of the vehicle travel controller using the objectrecognition apparatus according to the invention.

A vehicle travel controller 50A of the second embodiment illustrated inFIG. 9 is different from the above-described vehicle travel controller50 of the first embodiment in that a stationary object (hereinafter,simply referred to as a solid object) in front of the own vehicle isdetected and the other configurations are similar to those of thevehicle travel controller 50 of the first embodiment. Thus, in thedescription below, only a configuration different from the vehicletravel controller 50 of the first embodiment will be described. Further,the same reference numerals will be given to the same components asthose of the first embodiment and a detailed description thereof will beomitted.

As illustrated in the drawings, an object recognition apparatus 20A ofthe vehicle travel controller 50A includes a rear object detectiondevice 1A, a solid object detection device 2A, and a travel historycalculation device 3A.

The solid object detection device 2A is used to detect a solid object(for example, a guardrail or a wall provide along the vehicle lane) infront of the own vehicle and includes, for example, a stereo camera 8Awhich includes a plurality of cameras (front cameras) arranged on anupper portion of a wind shield of the own vehicle and capturing an imageof an environment in front of the own vehicle and a solid objectdetection unit 9A which detects the solid object in front of the ownvehicle on the basis of a plurality of images captured by the stereocamera 8A.

As illustrated in FIG. 10, the cameras constituting the stereo camera 8Acapture an image of a peripheral environment including a precedingvehicle VP traveling at the front side or a guardrail GR correspondingto a road-side solid object and transmit the captured image to the solidobject detection unit 9A.

The solid object detection unit 9A obtains a parallax for two left andright images on the basis of the information of the left and rightimages captured by the stereo camera 8A in order to detect the existenceof the solid object and to calculate a distance from the own vehicle tothe solid object. Further, a size of the solid object including heightinformation from a ground surface is obtained by the obtained distanceinformation and various information items are transmitted to the solidobject position estimation unit 4A of the travel history calculationdevice 3A. In the image captured by the stereo camera 8A in FIG. 10, therepresentative points of the detected solid object (here, the guardrailGR) are indicated as G1 to G3 in a direction from the front side.Further, in FIG. 11, the position of the representative point of thesolid object illustrated in FIG. 10 is indicated by G1: (xg_1, yg_1,zg_1), G2: (xg_2, yg_2, zg_2), and G3: (xg_3, yg_3, zg_3) in athree-dimensional coordinate system X-Y-Z using the own vehicle as anoriginal point. Further, FIGS. 10 and 11 show examples in which thepositions of the representative points of the solid object are detectedby three points, but the same applies to a case where two points or lessor four points or more are detected. Further, when the solid objectcontinuously exist along, for example, the vehicle lane, the positionsmay be approximated to a line or a curve in the X-Y plane of thecoordinate system.

A travel history calculation unit 11A of the travel history calculationdevice 3A calculates the coordinate system X(n+1)-Y(n+1) using the ownvehicle as an original point at the time t(n+1) from the coordinatesystem X(n)-Y(n) using the center of the own vehicle as an originalpoint at the time t(n) by the calculation described in the firstembodiment with reference to FIG. 4 and calculates a position changeamount (Δx, Δy) of the own vehicle VS for Δt=(t(n+1)−t(n)). Further, achange in direction of the own vehicle VS is also obtained by the samesequence as that of Equation (2) of the first embodiment and thecalculation result is transmitted to the solid object positionestimation unit 4A.

The solid object position estimation unit 4A converts the solid objectposition information output from the solid object detection device 2A tothe coordinate system using the center of the own vehicle as an originalpoint at a current time on the basis of a position change amount of theown vehicle obtained by the travel history calculation unit 11A andstores the conversion result in the solid object position informationstorage unit 10A. Regarding the conversion of the coordinate system atthat time, the conversion of the X-Y coordinate system is similar to theconversion indicated by Equation (4) in the first embodiment. However,in the second embodiment, since a change in position of the own vehicleincludes a movement in the axial direction within the X-Y plane (in theexample illustrated in the drawing, the horizontal plane) and therotation about the Z axis (the vertical axis), the information (height)in the Z direction of the solid object detected by the solid objectdetection device 2A is kept at the same value before and after theconversion of the coordinate.

In this way, the solid object position estimation unit 4A converts thesolid object position detected in the past into the coordinate systemusing the center of the own vehicle as an original point at a currenttime on the basis of the information obtained from the travel historycalculation unit 11A and the conversion result is stored in the solidobject position information storage unit 10A. At the same time, thesolid object position estimation unit 4A acquires solid object positioninformation at a current time point from the solid object detectiondevice 2A and additionally stores the solid object position informationin the solid object position information storage unit 10A.

Specifically, as illustrated in FIG. 12, the solid object positionestimation unit 4A first stores the solid object position informationoutput from the solid object detection device 2A at the time t(n) in thesolid object position information storage unit 10A. For example, asillustrated in FIGS. 10 and 11, as for the position information of thesolid object obtained from the image captured by the stereo camera 8A,the coordinate information (xg_1(t(n)), yg_1(t(n)), zg_1(t(n))),(xg_2(t(n)), yg_2(t(n)), zg_2(t(n))), (xr_3(t(n)), yr_3(t(n)),zg_3(t(n))) is stored as the position and height information items G1 toG3 in the coordinate system X-Y-Z using the center of the own vehicle asan original point at the time t(n).

Next, when the time elapses from t(n) to t(n+1), the solid objectposition estimation unit 4A converts the position information items G1to G3 of the solid object to the position information in the coordinatesystem X(n+1)-Y(n+1)-Z(n+1) using the center of the own vehicle as anoriginal point at the time t(n+1) by Equation (4) above and stores theconversion result in the solid object position information storage unit10A.

In accordance with a series of conversion, three-dimensional coordinateinformation from the position information items G1 to G3 of the solidobject detected at the time t(n) to the position information items Gm1to Gm3 of the solid object detected at the time t(n+m) is totally storedin the solid object position information storage unit 10A at the timet(n+m).

In addition, the solid object position information storage unit 10Astores the solid object position information altogether from the past.However, it is practically to sequentially delete the solid objectposition information stored for a predetermined time or more or thesolid object position information in which a distance from the ownvehicle becomes a predetermined value or more from the solid objectposition information storage unit 10A in order to prevent the overflowof the storage capacity.

In this way, when the solid object position information is recognized intime and the past solid object position information is used, theposition of the solid object behind the own vehicle can be accuratelyestimated.

The relative position calculation unit 5A is used to calculate arelative position of an object detected by the rear object detectiondevice 1A with respect to the position of the solid object behind theown vehicle stored in the solid object position information storage unit10A.

Specifically, when the rear object detection device 1A detects the leftrear target vehicle VT and the relative speed and the position (P2, Q2)of the target vehicle VT with respect to the own vehicle VS in the X-Yplane of the coordinate system using the center of the own vehicle as anoriginal point as illustrated in FIG. 13 or 14, the relative positioncalculation unit 5A selects two points closest to each other in thetraveling direction (the Y-axis direction) of the own vehicle VS fromthe solid object position information stored in the solid objectposition information storage unit 10A. In FIG. 13, the solid objectposition information items Gn1 and Gn2 are closest to each other in theY-axis direction. Then, the relative position calculation unit 5Aobtains a line connecting the positions Gn1 and Gn2 of tworepresentative points of the solid object, obtains an X-directiondistance xg_np at a place corresponding to the position of the targetvehicle VT in the Y-axis direction of the line, calculates a large/smallrelation between the value of the distance xg_np and the value P2 in theX-axis direction of the target vehicle VT, and transmits the calculationresult to the determination unit 6A.

The determination unit 6A determines whether the object detected by therear object detection device 1A exists in a predetermined area (forexample, an area where the reliability of the detection result obtainedby the rear object detection device 1A is low, that is, an area wherethe object detected by the rear object detection device 1A iserroneously detected due to the influence of the solid object) on thebasis of the large/small relation transmitted from the relative positioncalculation unit 5A.

Specifically, the determination unit 6A determines whether the targetvehicle VT exists at the inside (the own vehicle side) of the solidobject or the outside (the opposite side to the own vehicle), forexample, as illustrated in FIG. 13 on the basis of the large/smallrelation transmitted from the relative position calculation unit 5A,determines an influence of the solid object with respect to thedetection result of the target vehicle VT obtained by the radio waveradar 7A, and transmits the determination result to the control unit25A. For example, when the height included in the position informationitems Gn1 and Gn2 of two representative points of the solid object ishigher than the attachment position of the radio wave radar 7A, it isconsidered that the radio wave output from the radio wave radar 7A doesnot reach a position far from a line connecting two representativepoints of the solid object. FIG. 13 illustrates an example in which thevalue P2 in the X-axis direction of the target vehicle VT is larger thanthe distance xg_np from the Y axis to the solid object. However, in sucha case, it is determined that the reliability of the detection result ofthe target vehicle VT obtained by the rear object detection device 1A islow.

Further, for example, FIG. 14 illustrates an example in which a targetvehicle VT′ is detected by a radio wave radar 7 aA attached to a leftrear part of the own vehicle VS, the target vehicle VT is detected by aradio wave radar 7 bA attached to a right rear part of the own vehicleVS, and the position information items Gn1, Gn2, and Gn3 of threerepresentative points of the solid object are obtained by the solidobject position estimation unit 4A. In such a case, it is expected thatthe radio wave emitted from the radio wave radar 7A is reflected by thesolid object having a continuous shape. Thus, the target vehicle VTdetected by the radio wave radar 7 bA is real information, but thetarget vehicle VT′ detected by the radio wave radar 7 aA may beinformation of an erroneous target vehicle (a ghost of the targetvehicle VT) detected by the reflection of the radio wave from the solidobject. For that reason, even in such a case, it is determined that thereliability of the detection result of the target vehicle VT obtained bythe rear object detection device 1A is low.

In addition, in the examples illustrated in FIGS. 13 and 14, theposition information of the solid object is indicated by continuousdots, but when the solid object exists continuously along, for example,a road, the position information is approximated to a line or a curve.Then, this information may be stored as the position information of thesolid object in the three-dimensional coordinate system X-Y-Z.

The control unit 25A generates various control signals for controllingthe travel state and the like of the own vehicle on the basis of theinformation transmitted from (the determination unit 6A of the travelhistory calculation device 3A of) the object recognition apparatus 20A.

Specifically, when the determination unit 6A determines that the objectdetected by the rear object detection device 1A exists in apredetermined area (for example, an area where the reliability of thedetection result obtained by the rear object detection device 1A islow), the control unit 25A determines that there is low necessity for,for example, a steering control (regulation), a vehicle speed controlfor the own vehicle, and a warning (a warning sound or a warningdisplay) for the driver described in the first embodiment and generatescontrol signals for cancelling or suppressing the control.

A flow of a series of processes which is performed by theabove-described vehicle travel controller 50A will be described withreference to FIG. 15. First, in step S201, a solid object position inthe three-dimensional coordinate system X-Y-Z using the own vehicle asan original point is obtained by the solid object detection device 2A ofthe object recognition apparatus 20A according to the method describedwith reference to FIGS. 10 and 11.

Next, in step S202, the solid object position obtained in step S201 isstored in the solid object position information storage unit 10A as thecoordinate system using the own vehicle as an original point by thesolid object position estimation unit 4A of the travel historycalculation device 3A.

Next, in step S203, the movement amount of the own vehicle for Δtseconds is estimated on the basis of the information obtained by thesteering angle sensor 21A, the yaw rate sensor 22A, the vehicle wheelspeed sensor 23A, and the navigation system 24A constituting the vehicletravel controller 50A by the travel history calculation unit 11A. Theprocess in step S203 is similar to the process in step S103 of FIG. 8.

Next, in step S204, the solid object position information detected inthe past by the solid object detection device 2A using Equation (4)above is converted to the coordinate system using the own vehicle as anoriginal point at a current time by the solid object position estimationunit 4A to estimate the solid object behind the own vehicle position andis stored in the solid object position information storage unit 10A.

Next, in step S205, the rear object (the target vehicle or the like)including the rear side is detected by the rear object detection device1A and the position coordinate (P, Q) of the target vehicle is obtained.The process in step S205 is similar to the process in step S105 of FIG.8.

Next, in step S206, a relative position between the solid objectposition information stored in step S204 and the target vehicle detectedin step S205 is obtained by the relative position calculation unit 5A.More specifically, as described above, when the rear object detectiondevice 1A detects the target vehicle and detects the position (P, Q) ofthe target vehicle in the X-Y plane of the three-dimensional coordinatesystem using the own vehicle as an original point, the solid objectposition information of two points closest to each other in thetraveling direction (the Y-axis direction) of the own vehicle isselected from the solid object position information stored in the solidobject position information storage unit 10A. When an X-directiondistance between the target vehicle and the position of therepresentative point of the solid object for two points closes to eachother in the Y-axis direction is obtained, a relative position of thetarget vehicle with respect to the solid object can be estimated.

Next, in step S207, it is determined whether the target vehicle behindthe own vehicle exists in an area (a vehicle lane) corresponding to awarning object. In general, this determination is made based on acertain position of the target vehicle with respect to the own vehicle.However, when the vehicle lane position information described in thefirst embodiment is obtained, it is possible to accurately determine acertain vehicle lane (a vehicle lane on which the own vehicle travels, aright adjacent vehicle lane, a left adjacent vehicle lane, or two ormore separated vehicle lanes) on which the target vehicle travels.

When it is determined that the target vehicle exists in an area (avehicle lane) corresponding to a warning object in step S207, it isdetermined whether the vehicle detected by the rear object detectiondevice 1A exists in an area where the reliability of the detectionresult obtained by the rear object detection device 1A is low, that is,the vehicle detected by the rear object detection device 1A is a vehicleerroneously detected by the influence of the solid object in step S208according to the method described with reference to FIGS. 13 and 14 onthe basis of the information of the relative position of the targetvehicle with respect to the solid object obtained in step S206.

When it is determined that the vehicle detected by the rear objectdetection device 1A is not a vehicle erroneously detected by theinfluence of the solid object in step S208, it is determined whether awarning sound is actually output due to the target vehicle on the basisof the information of the position and the speed (for example,information on whether the target vehicle approaches the own vehicle) ofthe target vehicle in step S209.

Then, when it is determined that a warning sound needs to be actuallyoutput in step S209, a control signal is generated by the control unit25A to output a warning sound in step S210.

The processes in step S209 and step S210 are similar to those of stepS108 and step S109 of FIG. 8.

In addition, a series of these processes are repeated whenever ΔTseconds elapse.

In this way, according to the second embodiment, in the vehicle thatdetects an object existing at the rear side including the oblique rearside of the own vehicle by the radio wave radar 7A such as a millimeterwave radar, the solid object in front of the own vehicle is detected onthe basis of a plurality of images captured by the stereo camera 8Acapturing an image of an environment in front of the own vehicle, theposition of the solid object behind the own vehicle is estimated on thebasis of the detected solid object and the travel history of the ownvehicle, and the relative position of the object existing behind the ownvehicle with respect to the estimated position of the solid object iscalculated. Accordingly, it is possible to accurately recognize theposition of the object existing at the rear side including the obliquerear side of the own vehicle, that is, the vehicle lane on which theobject is located.

<Third Embodiment>

FIG. 16 is a configuration diagram illustrating a third embodiment of avehicle travel controller using the object recognition apparatusaccording to the invention.

A vehicle travel controller 50B of the third embodiment illustrated inFIG. 16 is different from the above-described vehicle travel controller50 of the first embodiment in that a vehicle lane behind the own vehicleis detected by a camera capturing an image of an environment behind theown vehicle and the other configurations are similar to those of thevehicle travel controller 50 of the first embodiment. Thus, in thedescription below, only a configuration different from the vehicletravel controller 50 of the first embodiment will be described. Further,the same reference numerals will be given to the same components asthose of the first embodiment and a detailed description thereof will beomitted.

As illustrated in the drawings, an object recognition apparatus 20B ofthe vehicle travel controller 50B includes a rear object detectiondevice 1B, a vehicle lane detection device 2B, and a travel historycalculation device 3B similarly to the vehicle travel controller 50 ofthe first embodiment. However, in the third embodiment, a camera (animage sensing device) 8B of the vehicle lane detection device 2B isattached to the rear side of the own vehicle (see FIG. 18).

The vehicle lane detection device 2B is used to detect a vehicle lane (avehicle travel lane) behind the own vehicle and includes, for example,the camera (the rear camera) (the image sensing device) 8B which isdisposed at the rear part of the own vehicle and captures an image of anenvironment behind the own vehicle and a vehicle lane detection unit 9Bwhich detects a vehicle lane behind the own vehicle on the basis of theimage captured by the camera 8B.

The camera 8B is configured as, for example, a CMOS camera and isattached to the own vehicle to have an optical axis directed obliquelydownward at the rear side of the own vehicle.

Then, as illustrated in FIG. 17, the camera 8B captures an image of aperipheral environment including a road in the range of about 10 mbehind the own vehicle and transmits the captured image to the vehiclelane detection unit 9B. Further, here, a detection area (an imagecapturing area) Ac of the camera 8B is smaller than detection areas Aaand Ab of radio wave radars 7B (7 aB and 7 bB) constituting the rearobject detection device 1B. More specifically, the detection areas Aaand Ab behind the own vehicle of the radio wave radars 7B (7 aB and 7bB) are larger than a detection area (an image capturing area) Ac behindthe own vehicle of the camera 8B. Thus, the radio wave radars 7B (7 aBand 7 bB) are able to detect an object existing at the further rear side(particularly, the rear side) from the own vehicle in relation to thecamera 8B (see FIG. 18).

The vehicle lane detection unit 9B performs, for example, a binarizationprocess or a feature point extraction process based on the imagecaptured by the camera 8B to select a pixel (a road dividing linecandidate point) which is considered as a road dividing line (a whiteline, a yellow line, a broken line, or bott's-dots) on a road from theimage, recognizes continuously arranged road dividing line candidatepoints as a road dividing line constituting the vehicle lane to obtainthe position thereof, and transmits information on the position to thevehicle lane position estimation unit 4B of the travel historycalculation device 3B. In the image captured by the camera 8Billustrated in FIG. 17, the positions of the road dividing line at theright side (the right side when viewed in the traveling direction of thevehicle) are indicated by Rc1 and Rc2 in a direction from the front sideand the positions of the road dividing line at the left side (the leftside when viewed in the traveling direction of the vehicle) areindicated by Lc1 and Lc2 in a direction from the front side. In FIG. 18,as for the positions of the road dividing lines illustrated in FIG. 17,the positions in the coordinate system X-Y using the center of the ownvehicle as an original point are respectively indicated by Rc1: (xcr_1,ycr_1), Rc2: (xcr_2, ycr_2), Lc1: (xcl_1, ycl_1), and Lc2: (xcl_2,ycl_2). Additionally, in FIGS. 17 and 18, examples are described inwhich the position of the road dividing line is obtained as two pointsfor each of the left and right sides, but the same applies to a casewhere one or three points or more are obtained or a case where theposition is approximated to a line or a curve.

Further, various methods have been developed to recognize the roaddividing line or the vehicle lane defined by the road dividing line. Forexample, a method of extracting a road shoulder or a median strip by apattern matching can be also used. Further, the vehicle lane detectiondevice 2B can be, of course, commonly used together with various vehiclelane detection devices used in, for example, a vehicle lane keep assistdevice (also referred to as a lane keep assist) or a vehicle lanedeparture warning device (also referred to as a lane departure warning).

A travel history calculation unit 11B of the travel history calculationdevice 3B calculates the coordinate system X(n+1)-Y(n+1) using the ownvehicle as an original point at the time t(n+1) from the coordinatesystem X(n)-Y(n) using the center of the own vehicle as an originalpoint at the time t(n) by the calculation described with reference toFIG. 4 in the first embodiment and calculates a position change amount(Δx, Δy) of the own vehicle VS for Δt=(t(n+1)−t(n)). Further, a changein direction of the own vehicle VS is also obtained by the same sequenceas that of Equation (2) of the first embodiment and the calculationresult is transmitted to the solid object position estimation unit 4B.

The vehicle lane position estimation unit 4B converts the vehicle laneposition detected in the past to the coordinate system using the centerof the own vehicle as an original point at a current time on the basisof the information obtained from the travel history calculation unit 11Bby the calculation described with reference to FIG. 4 in the firstembodiment and stores the conversion result in the vehicle lane positioninformation storage unit 10B. At the same time, the vehicle laneposition estimation unit 4B acquires the vehicle lane positioninformation at a current time point from the vehicle lane detectiondevice 2B and additionally stores the vehicle lane position informationin the vehicle lane position information storage unit 10B.

Specifically, as illustrated in FIG. 19, the vehicle lane positionestimation unit 4B first stores the vehicle lane position informationoutput from the vehicle lane detection device 2B at the time t(n) in thevehicle lane position information storage unit 10B. For example, asillustrated in FIGS. 17 and 18, the coordinate information (xcr_1(t(n)),ycr_1(t(n))), (xcr_2(t(n)), ycr_2(t(n))) is stored while a position(that is, vehicle lane information) of a right road dividing lineobtained from an image captured by the camera 8B is set as positions Rc1and Rc2 of the coordinate system X-Y using the center of the own vehicleas an original point at the time t(n). Similarly, although there is nodescription in FIG. 19, the coordinate information (xcl_1(t(n)),ycl_1(t(n))), (xcl_2(t(n)), ycl_2(t(n))) is stored while a position(that is, vehicle lane information) of a left road dividing lineobtained from an image captured by the camera 8B is set as positions Lc1and Lc2 in the coordinate system X-Y using the center of the own vehicleas an original point.

Next, when the time elapses from t(n) to t(n+1), the vehicle laneposition estimation unit 4B converts the positions Rc1 and Rc2 of theright road dividing line and the positions Lc1 and Lc2 of the left roaddividing line to the position information in the coordinate systemX(n+1)-Y(n+1) using the center of the own vehicle as an original pointat the time t(n+1) by Equation (4) above and stores the conversionresult in the vehicle lane position information storage unit 10B.

In accordance with a series of conversion, coordinate information fromthe positions Rc1 and Rc2 of the right road dividing line detected atthe time t(n) to the positions Rcm1 and Rcm2 of the right road dividingline detected at the time t(n+m) is stored as the vehicle lane positioninformation in the vehicle lane position information storage unit 10B atthe time t(n+m) (see FIG. 19). Similarly, even in the left road dividingline, the position information of the road dividing line detected by thevehicle lane detection device 2B from the time t(n) to the time t(n+m)is stored as the vehicle lane position information in the vehicle laneposition information storage unit 10B.

In addition, the vehicle lane position information storage unit 10Bstores the vehicle lane position information altogether from the past.However, it is practical to sequentially delete the vehicle laneposition information stored for a predetermined time or more or thevehicle lane position information in which a distance from the ownvehicle becomes a predetermined value or more from the vehicle laneposition information storage unit 10B in order to prevent the overflowof the storage capacity.

In this way, when the vehicle lane position information is recognized intime and the past vehicle lane position information is used, the vehiclelane position behind the own vehicle (the vehicle lane position behindthe detection area (the image capturing area) Ac of the camera 8B) canbe accurately estimated.

The relative position calculation unit 5B and the determination unit 6Bdetermine, for example, whether the rear target vehicle VT exists on theright adjacent vehicle lane with respect to the vehicle lane on whichthe own vehicle VS travels (see FIG. 6) or the target vehicle VT existsat the rear side of the same vehicle lane on which the own vehicle VStravels (see FIG. 7) by the calculation described with reference toFIGS. 4 to 7 in the first embodiment.

The control unit 25B, can also generate various control signals forcontrolling the travel state and the like of the own vehicle on thebasis of the information transmitted from (the determination unit 6B ofthe travel history calculation device 3B of) the object recognitionapparatus 20B by the calculation described in the first embodiment.

In addition, since a flow of a series of processes performed by thevehicle travel controller 50B of the third embodiment is substantiallysimilar to a flow of a series of processes performed by the vehiclecontrol device 50 of the first embodiment, a detailed descriptionthereof will be omitted.

In this way, according to the third embodiment, for example, in thevehicle that detects an object existing at the rear side including theoblique rear side of the own vehicle by the radio wave radar 7B such asa millimeter wave radar having a large detection range behind the ownvehicle compared with the camera 8B, the vehicle lane behind the ownvehicle is detected on the basis of the image captured by the camera 8Bcapturing an image of an environment behind the own vehicle, theposition of the vehicle lane at the rear side (particularly, the rearside of the detection area (the image capturing area) Ac of the camera8B) of the own vehicle is estimated on the basis of the detected vehiclelane and the travel history of the own vehicle, and the relativeposition of the object existing behind the own vehicle with respect tothe estimated position of the vehicle lane is calculated. Accordingly,it is possible to accurately and promptly recognize the position of theobject existing at the rear side including the oblique rear side of theown vehicle, that is, the vehicle lane on which the object is locatedeven when the own vehicle travels on a curve or changes the vehiclelane.

In addition, in the description above, the first embodiment, the secondembodiment, and the third embodiment have been described separately.However, a combination of these embodiments may be used. That is, thevehicle lane and the solid object at the front or rear side of the ownvehicle are detected on the basis the image captured by the cameracapturing an image of a front or rear environment, the positions of thevehicle lane and the solid object behind the own vehicle are estimatedon the basis of the detected vehicle lane, the detected solid object,and the travel history of the own vehicle, and the relative positions ofthe object existing behind the own vehicle with respect to the estimatedpositions of the vehicle lane and the solid object are calculated.Accordingly, it is possible to further accurately recognize the positionof the object existing at the rear side including the oblique rear sideof the own vehicle, that is, the vehicle lane on which the object islocated.

Further, in the first to third embodiments, an example has beendescribed in which the speed information of the own vehicle is acquiredby the vehicle wheel speed sensor, but the speed information of the ownvehicle may be acquired by a unit or a device other than the vehiclewheel speed sensor.

Further, in the above-described second embodiment, an example has beendescribed in which the solid object is detected by the stereo cameraincluding a plurality of cameras, but the solid object may be detectedby a monocular camera.

Further, in the third embodiment, an example has been described in whichthe monocular camera is attached while being directed backward so thatthe vehicle lane behind the own vehicle is detected. However, a stereocamera including a plurality of cameras may be attached while beingdirected backward so that the vehicle lane or the solid object behindthe own vehicle is detected and the position of the vehicle lane or theposition of the solid object behind the own vehicle (particularly, atthe rear side of the detection area (the image capturing area) of thestereo camera) may be estimated on the basis of the detection result.

In addition, the invention is not limited to the first to thirdembodiments and includes various modified examples. For example, thefirst to third embodiments are merely used to easily describe theinvention and may not essentially include all configurations describedabove. Further, a part of a certain embodiment can be replaced by theconfigurations of the other embodiments and the configurations of theother embodiments may be added to the configuration of a certainembodiment. Further, a part of the configurations of the embodiments canbe added, deleted, or replaced.

Further, only control lines or information lines necessary fordescription are depicted in the drawings and all control lines orinformation lines necessary for a product are not depicted in thedrawings. In fact, it may be considered that all configurations areconnected to one another.

REFERENCE SIGNS LIST

-   1, 1A, 1B rear object detection device-   2, 2B vehicle lane detection device-   2A solid object detection device-   3, 3A, 3B travel history calculation device-   4, 4B vehicle lane position estimation unit-   4A solid object position estimation unit-   5, 5A, 5B relative position calculation unit-   6, 6A, 6B determination unit-   7, 7A, 7B radio wave radar (rear object detection unit)-   8 front camera (image sensing device)-   8A stereo camera (image sensing device)-   8B rear camera (image sensing device)-   9, 9B vehicle lane detection unit-   9A solid object detection unit-   10, 10B vehicle lane position information storage unit-   10A solid object position information storage unit-   11, 11A, 11B travel history calculation unit-   20, 20A, 20B object recognition apparatus-   21, 21A, 21B steering angle sensor-   22, 22A, 22B yaw rate sensor-   23, 23A, 23B vehicle wheel speed sensor-   24, 24A, 24B navigation system-   25, 25A, 25B control unit-   GR guardrail-   VP preceding vehicle-   VS own vehicle-   VT target vehicle

The invention claimed is:
 1. An object recognition apparatus thatrecognizes a position of an object existing behind an own vehicle,comprising: an image sensing device that captures an image of anenvironment at the front or rear side of the own vehicle; a vehicle lanedetection unit that detects a vehicle lane at the front or rear side ofthe own vehicle on the basis of the image captured by the image sensingdevice; a vehicle lane position estimation unit that estimates aposition of a vehicle lane behind the own vehicle on the basis of thevehicle lane detected by the vehicle lane detection unit and a travelhistory of the own vehicle; a rear object detection unit that detects anobject existing behind the own vehicle; a relative position calculationunit that calculates a relative position of the object detected by therear object detection unit with respect to the position of the vehiclelane estimated by the vehicle lane position estimation unit; adetermination unit that determines whether the object exists on apredetermined vehicle lane on the basis of the relative position of theobject calculated by the relative position calculation unit, includingdetermining whether the object exists at an inside or an outside of aright road dividing line; and a travel history calculation unit thatcalculates the travel history of the own vehicle based on informationobtained from a vehicle speed sensor, a yaw rate sensor, a steeringangle sensor, and a navigation system.
 2. The object recognitionapparatus according to claim 1, wherein the vehicle lane detection unitdetects a vehicle lane at the front or rear side of the own vehicle byextracting a road dividing line at the front or rear side of the ownvehicle from the image captured by the image sensing device.
 3. Theobject recognition apparatus according to claim 1, wherein the imagesensing device is configured as a monocular camera.
 4. The objectrecognition apparatus according to claim 1, wherein the rear objectdetection unit is configured as a radio wave radar.
 5. A vehicle travelcontroller that controls a travel state of an own vehicle based on aposition of an object, comprising: a control unit that generates controlsignals for controlling the travel state of the own vehicle; and anobject recognition apparatus that recognizes the position of the objectexisting behind the own vehicle, the object recognition apparatusincluding an image sensing device that captures an image of anenvironment at the front or rear side of the own vehicle; a vehicle lanedetection unit that detects a vehicle lane at the front or rear side ofthe own vehicle on the basis of the image captured by the image sensingdevice; a vehicle lane position estimation unit that estimates aposition of a vehicle lane behind the own vehicle on the basis of thevehicle lane detected by the vehicle lane detection unit and a travelhistory of the own vehicle; a rear object detection unit that detects anobject existing behind the own vehicle; a relative position calculationunit that calculates a relative position of the object detected by therear object detection unit with respect to the position of the vehiclelane estimated by the vehicle lane position estimation unit; adetermination unit that determines whether the object exists on apredetermined vehicle lane on the basis of the relative position of theobject calculated by the relative position calculation unit, includingdetermining whether the object exists at an inside or an outside of aright road dividing line; and a travel history calculation unit thatcalculates the travel history of the own vehicle based on informationobtained from a vehicle speed sensor, a yaw rate sensor, a steeringangle sensor, and a navigation system.
 6. The vehicle travel controlleraccording to claim 5, wherein a warning is generated when thedetermination unit determines that the object exists on a predeterminedvehicle lane.
 7. An object recognition apparatus that recognizes aposition of an object existing behind an own vehicle, comprising: animage sensing device that captures an image of an environment at thefront or rear side of the own vehicle; a solid object detection unitthat detects a stationary object at the front or rear side of the ownvehicle on the basis of the image captured by the image sensing device;a solid object position estimation unit that estimates a position of thestationary object behind the own vehicle based on the stationary objectdetected by the solid object detection unit and a travel history of theown vehicle; a rear object detection unit that detects an objectexisting behind the own vehicle; a relative position calculation unitthat calculates a relative position of the object detected by the rearobject detection unit with respect to the position of the stationaryobject estimated by the solid object position estimation unit; adetermination unit that determines whether the object exists in apredetermined area based on the relative position of the objectcalculated by the relative position calculation unit, includingdetermining whether the object exists at an inside or an outside of aright road dividing line; and a travel history calculation unit thatcalculates the travel history of the own vehicle based on informationobtained from a vehicle speed sensor, a yaw rate sensor, a steeringangle sensor, and a navigation system.
 8. The object recognitionapparatus according to claim 7, wherein the image sensing deviceincludes a plurality of cameras.
 9. The object recognition apparatusaccording to claim 7, wherein the rear object detection unit isconfigured as a radio wave radar.
 10. A vehicle travel controller thatcontrols a travel state of an own vehicle based on a position of anobject, comprising: a control unit that generates control signals forcontrolling the travel state of the own vehicle; and an objectrecognition apparatus that recognizes the position of the objectexisting behind the own vehicle, the object recognition apparatusincluding an image sensing device that captures an image of anenvironment at the front or rear side of the own vehicle; a solid objectdetection unit that detects a stationary object at the front or rearside of the own vehicle on the basis of the image captured by the imagesensing device: a solid object position estimation unit that estimates aposition of the stationary object behind the own vehicle based on thestationary object detected by the solid object detection unit and atravel history of the own vehicle; a rear object detection unit thatdetects an object existing behind the own vehicle; a relative positioncalculation unit that calculates a relative position of the objectdetected by the rear object detection unit with respect to the positionof the stationary object estimated by the solid object positionestimation unit; a determination unit that determines whether the objectexists in a predetermined area based on the relative position of theobject calculated by the relative position calculation unit, includingdetermining whether the object exists at an inside or an outside of aright road dividing line; and a travel history calculation unit thatcalculates the travel history of the own vehicle based on informationobtained from a vehicle speed sensor, a yaw rate sensor, a steeringangle sensor, and a navigation system.
 11. The vehicle travel controlleraccording to claim 10, wherein a warning is generated when thedetermination unit determines that the object exists in a predeterminedarea.